


Coffee with serial killers

by cannibalpasta



Category: Teen Wolf (TV)
Genre: Alternate Universe - Law Enforcement, Alternate Universe - Police, Angst, Blood and Violence, Detective!Stiles, Fluff, Kidnapping, M/M, Mild Gore, Mystery, Smut, Stiles-centric, fed!Derek, lots of bad coffee
Language: English
Status: In-Progress
Published: 2017-06-06
Updated: 2017-09-11
Packaged: 2018-11-09 12:57:30
Rating: Explicit
Warnings: Graphic Depictions Of Violence
Chapters: 3
Words: 13,278
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11105028
Author URL: https://archiveofourown.org/users/cannibalpasta/pseuds/cannibalpasta
Summary: The case is like water, slipping right through their fingers.-- Cop AUIn which Stiles is a police detective hunting down a serial killer, and Derek is an FBI agent that gets sent to help him with the investigation. Sleepless nights, bad coffee and a crazy manhunt ensues.





	1. A Fresh Set of Eyes

**Author's Note:**

> Yeah, so I'm probably gonna fail this one class, but at least I got to write my first ever Sterek fic, whoop

**Notes for the Chapter:**

> So, I'm in the middle of like a million other WIPs right now, but this fic's not going to be that long anyway (I'm currently at nearly 18K words, but the word count will probably be around 20K when I'm finished), so I'm posting this anyway.
> 
> Now, let's get on with the fic. I hope you enjoy reading! :)

A manilla folder slams against his desk.

"We've got another vic," Allison informs him, as if slamming folders against desks is the norm here, and reaches over to grab Stiles' coffee mug.

Stiles sighs as he watches his coffee being consumed without him involved. "Rough night, huh?" he prods, snatching the folder and flipping through the contents. He freezes when he recognizes what's inside.

"You wouldn't believe me," Allison replies and places the mug, now half-empty, back to his desk. She nods toward the file in Stiles' hands. "The guys that got the call thought this was just another homicide, but forensics connected it to our killer. So, it's our case now."

Stiles nods, biting his lip a little, and pulls out the crime scene photos. They are fresh, just taken a few hours ago, but he still would've preferred to take a look himself, live at the undisturbed murder scene. "Deaton and Scott got a look at him yet?"

"Yeah, he's down at morgue, but it's only been a little over an hour, so their profiling is most likely still in the making. Anyhow, we should go take a look." When they reach the elevator, Allison takes a hold of his shoulder and looks him dead in the eye. "You okay?"

He smiles at her, but it feels somewhat strained. "Yeah, I'm good."

She indulges him with a rueful smile and claps his back. The elevator doors open and they walk up to the two medical examiners in the room. It's always a little chilly down at the morgue, and Stiles ends up rubbing his arms a little as they cross the floor.

"Hey," Allison greets her husband, giving him a quick peck on the cheek, and Scott brightens up like a beacon. It's almost inhuman, the happiness radiating off of Stiles' best friend.

"Hi," Scott replies her, and then reaches out to pat Stiles's arm. "Hi, buddy."

"Yo," Stiles says, and then offers Deaton a quick 'good morning, Doc'.

Then he steps closer to the examination table and looks down at the body silently laying on top of it. The man is young, clearly over twenty, but not a day over thirty, with a pale complexion and dark brown hair. He's on the skinny side, although not underweight in any sense, and his limbs look long and athletic, especially now that they are stretched out on the table like this.

Stiles feels a little disconnected for a moment, like he's driving down the highway hands free, as he watches the unfocused, cloudy brown eyes surrounded by a slight tache noir, staring up at nothing, and the mottled, discoloured patches of skin all over the man's body.

A warm hand touches his shoulder, and suddenly he's grounded again. He looks over, and sees that the hand is connected to Deaton. The medical examiner arches an eyebrow at him, but doesn't say anything, and Stiles is grateful for it. He nods and Deaton removes his hand.

"The wounds inflicted upon the victim are consistent with the ones on the other victim's of your guy. He also fits the profile to the dot. Male, young, white, brown hair. The method of killing is also the same; signs of a struggle, multiple stabbing wounds to the abdomen, death caused by blood loss. The murder weapon even seems to be almost identical to the one used on that guy a month back...."

"Myers," Scott and Stiles supply at the same time.

"Yes, him. A sturdy hunting knife, most likely. And of course, the killer left another picture."

Stiles forces his hands to loosen from the tight fists they had curled into of their own accord, and pushes them into the pockets of his trousers. "Is it with the forensics?"

Deaton spares him an appraising look. "Yes, it is. I'm sure you'll get a look at it and the rest of the evidence as soon as they are finished. Now, here," he says and hands Allison a thin folder, "is the first draft of our report. There is all I just told you and then a little more in detail. We'll be handing over our final description once the forensics get a match for the fingerprints." The senior examiner nods at them his clear dismissal, and Allison takes Stiles from his elbow as she leads them back to the elevator.

She slaps the folder at Stiles' chest for him to hold. Stiles is convinced she has a thing for slamming and slapping manilla. Perhaps he should ask Scott about it. On second thought, perhaps not.

"You lied."

Stiles blinks and frowns at the accusation. "I did not."

"Did too."

"I didn't--" he sighs frustratedly. "I wasn't lying. I'm fine, okay?"

Allison cocks a skeptical eyebrow at him.

"I am! I just don't like looking at dead people, alright? Like any sane person wouldn't." He narrows his eyes at her. "Also, I hate that look, stop it. Nothing good ever comes out of that look."

Allison rolls her eyes at him and walks out of the elevator as the doors slide open. "Don't be a brat, Stiles. Now, come on, we've got work to do."

He sighs at her back, but follows.

Truth is, there's not much work to be done before they get the identity of the newest victim. During the course of fourteen months, there has been four individual homicides committed by the same killer, this one marking the fifth one, and Stiles and Allison haven't left as much as a single stone turned while investigating the case, bending backwards to find the person responsible, but to no avail. This case is like water, slipping right through their fingers.

Stiles groans and chucks the pile of photos to his desk, scattering them on top of older photos and profiles. "I say we go to the crime scene while the forensics are still at it. I'll go nuts if I have to read another word."

Allison sighs as if in agreement, and raises somewhat bloodshot eyes from her desk. "Agreed. But you're driving, I'm too tired to function. And we're getting coffee on the way. I hate that crap they make in the break room."

"Seemed to suit your tastes just fine half an hour ago," Stiles mutters as he holsters his gun and pulls his suit jacket on. Allison rewards his quip with a whack to his upper arm.

True to her word, Allison even nods off a of couple times as they drive to first get coffee, and then to the crime scene that's still closed off from the public. She has taken the mantle of showing the reigns to the rookies, so it's often double the paperwork for her. Stiles tries to stay overtime to help her sometimes, but when it's about some major fuck-up done by a freshly commissioned officer of the law (which happens surprisingly often), there's really not much he can do.

Allison's dad, Chris Argent, works in the strategic management, and that's where she wants to someday end up at too, being the ambitious bastard she is. And so, apparently that's reason enough to work oneself to the brink of exhaustion. Stiles frowns when he pulls to a halt by the curb, thinking that he should remind her what Scott (and Stiles, Chris, etc.) think of her self-destructive overachieving.

He decides to take sadistic joy out of blaring the horn of the car and startling his fellow detective to alertness. She slaps the back of his head for his troubles, much like Stiles' own dad would, and takes a mighty swig from her coffee that had been resting in the cupholder above the center console.

The murder scene is another back alley, as had one of the killer's previous murder scenes been, and it's closed off with yellow tape, as a few evidence technicians and police officers keeping a lookout still linger.

"Good morning, Detective Argent, Detective Stilinski," a familiar female officer greets them. She's one of Allison's rookies, looking to advance to the rank of a detective in a year or two.

"Morning, Kira," Allison replies her, smiling. "But please, just call me Allison already."

She grins. "Sure thing," she says, but Stiles is quite sure she's going to keep being a little shit and calling her by the honorific anyway, since she knows that Allison hates it. Stiles already knows he's going to like her once they'll get to properly work together.

"We actually came to take a look at the crime scene," he interjects before Allison has the time to get heated, and Yukimura shifts her knowing fox eyes from her to him. _Oh_ , yes, Stiles knows that they'll get to prank and annoy the whole department together one day.

"Of course. Go ahead then," she replies easily and holds up the yellow tape for them to duck under.

The alleyway is pretty standard, as far as crime scenes go. Two brick walls, some dumpsters and a puddle of blood on the asphalt. It's still not completely dried up, since there's too much of if to dry in the five to six or so hours after it was first spilled, and Stiles crouches before to the puddle. Allison moves to stand next to him.

"It's not your fault, you know."

Stiles bites his lip. "I know that, Ally."

"I don't think you do." Then she turns away from the puddle to take a look at the wall by their left. Stiles gets up to follow his partner.

"That's where..." he starts.

"Where the photo was, yeah," she finishes for him. She pulls on a latex glove to trace the metal pipe, index finger brushing over the flaking blood around the thin hole left behind from the murder weapon -- now, already removed by evidence technicians. As it happens, a part of the serial killer's modus operandi is attaching a photo to some part of the murder scene, using the murder weapon, of course, and this killing is no exception.

Stiles sighs and brushes a hand through his hair. "This was a moot plan. There's nothing here for us to look at anymore."

"Come on, don't be like that," Allison says. "At least we got the general feeling of the crime scene now. And coffee, let's not forget that."

Stiles shakes his head at her, smiling despite himself. "Sure, if you say so."

"I do say so," she adds unnecessarily, and removes her glove to mess with his hair. "Now, have we seen enough already, or do you wanna look around for a bit more? I know that you're way too invested in this case, but it can be of advantage at times."

He huffs and looks around, hand back in his hair to comb it in place now that Allison removed all order from it. "No, I think I'm good. Also, I'm dropping you off at your place, you're taking the morning off. Scott will kill me if he ever finds out that I let you work when you're as exhausted as you are."

She groans, but the fact that she doesn't argue is testament enough to how tired she really is. "Alright then, Detective Stilinski." She glances at her wristwatch. "Pick me up at ten. Four hours should be enough for me to freshen up."

"Make that eleven, and you've got yourself a deal, Detective Argent."

She chuckles and shoves at him when he ducks beneath the tape, Yukimura again holding it up for them.

 

* * *

 

It's afternoon when his dad finally comes to find him.

"So, I hear there's been another victim." He doesn't need to specify about which case he's talking about. Stiles sighs and scratches his neck.

"Seems like it, yeah."

"How are you holding up?" he asks, and Stiles looks up to meet his concerned, grey-green eyes. His dad is the Chief of the Beacon Hills City Police Department, well-praised and trusted for the years he's spent in the force. In short, his father is a good man, and Stiles feels lucky to be raised by him, mom or no mom included.

"I'm fine, Dad," he says, going as far as calling him with a word reserved only to be used outside of work, which is the principle that they usually make a point of following. It's not that no one knows of their relation, with what their shared last name and all, but there's no point in cultivating it, especially since they are supposed to act like a superior and a subordinate anyway.

The chief's eyes soften at the use of 'dad', and Stiles already regrets saying it. He was supposed to convince the old man that he's just peachy, damn it.

His dad bends a little from the waist to grasp his neck in a firm hold, before slipping away to do whatever needs to be done now. Never let it be said that the chief isn't a busy man.

Stiles sighs and brushes a hand over his eyes. This case is really getting to his frayed nerves and beneath his usually thick skin.

"Wanna go grab lunch?" Allison asks from her desk. She had been privy to him and his dad's earlier exchange, but Stiles is a-okay with that. He trusts her, as it happens, and she's not the type to judge him.

"Sure, I guess I could eat something."

They get themselves sprout salads and return to eat them at their workstations, managing to get to halfway done before Stiles' dad returns with an urgent look on his face.

"Hey, what's up?" Stiles asks, straightening in his chair as he lifts his feet off of his desk and back to the floor. His father doesn't even give him a dirty look for the fact, but that may as well be only because he has something more important to talk about.

"I just had a video conference with the FBI. They are sending their guys in to investigate your killer."

Stiles almost chokes on his salad. _"What?"_

His dad gives a little shake of his head. "You know how this goes. Serial killers are FBI's speciality. It's a wonder we have been able to hold onto this case even as long as we have."

"Uh, we have been able to hold onto it because it involves our people. Involves me, to be precise."

"Don't think I don't know that, Stiles," his dad says pointedly. "But the director of their California branch has had enough. I agreed with her that a team will be joining our investigation here."

"No," Stiles states firmly.

"Stiles," Allison says evenly. "We could use a little help, don't you think?"

"I don't want outsiders involved."

"We know that, Stiles, but the investigation is not moving forward. Maybe these people can provide a fresh set of eyes."

"Allison is right, son. I know this is tough for you, but we don't make the rules. Director Martin's team will be here first thing tomorrow morning."

Stiles groans. "I hate feds."

Allison chuckles. "They can be asshats, alright. But let's see what happens. Maybe these people are okay."

"I doubt it," he says moodily and shoves more sprouts into his mouth. He misses the amused look his dad and Allison share over his head.

 

* * *

  

Turns out, his prediction isn't that much far off. Especially when it comes to Special Agent Eyebrows.

The feds had arrived in the crack of the dawn, and his father had been the one to first greet them and usher them up to the conference room for a briefing. Which, apparently, they had chosen was unnecessary.

"We have done our homework, Chief Stilinski," Eyebrows had told his dad, his team moving restlessly behind his back, like a pack of wolves ready to be set free for a hunt.

His dad had just flashed his Disapproving Dad Look #21, and promptly told the guys to sit their asses down, get a cup of joe or something from the vending machine, and wait for the briefing to start. Stiles had seen the exchange from his workstation as he'd been putting the last of his and Allison's presentation together, and had sent a glare in Agent Eyebrows' way. Fucking feds.

Now, ten minutes later -- which he may have more or less intentionally dawdled through, just to make the FBI agents wait, much to Allison's exasperation -- he and his partner are walking through the door to the conference room.

Agent Eyebrows is the first to glue his intimidating eyes on Stiles and Allison, but the two detectives have enough experience in dealing with tough people under their belt to not feel threatened.

"Morning, guys," Stiles greets the agents with fake cheer. "I'm Detective Stiles Stilinski, and this is my partner, Detective Allison Argent."

"Good morning," Allison says with a dazzling smile. "We'll be briefing you about the case we'll be working on together."

Eyebrows has the nerve to sigh slowly through his enviously well-shaped nose. "With all due respect, my team and I have already been briefed on this case."

"With an equal amount of _all-due-respect,_ the two of us still have the home-field advantage here," Stiles cuts in with, voice as steely as his father's when he's scolding his subordinates. "As well as good, concrete memory of all the victims, murder scenes, et cetera," he adds, accompanying his sentence with a flourish of his hand. "Also, this is supposed to be a joint operation, so we'll be expecting a little more cooperation from you guys. Does that sound reasonable, Agent...?"

"Hale," the special agent in charge, aka Eyebrows bites out, eyes gauging Stiles intently.

"...Hale?" he finishes.

"Yes, it sounds reasonable, Detective Stilinski." Hale leans back in his chair more comfortably, as if he hadn't been planning to ditch the briefing all along. "I suppose you two want to know my team, as well."

"If you wouldn't mind, agent," Allison smiles, deceptively sweetly.

"Special Agents Reyes, Boyd and Lahey." He motions to each agent respectively, as he rattles on their names. "Lahey is also specialized in forensic science, so he would like to consult your forensics and medical examiners about this case. I'm the senior special agent, so the jurisdiction of this case now falls to me."

Stiles bristles at the statement, but brushes it off quickly. He'll show Agent Muscles here who has the _jurisdiction_ , or what ever.

He flashes a tight smile that most likely screams _fake_ and _trouble_ at Hale, and replies with a snotty tone, "Sir."

The senior agent seems more amused than anything by Stiles' attitude, and gives them a slight nod. "You may proceed with the presentation."

Stiles purses his lips irritably and watches as Hale's team smirks up at the two of them from behind their senior's back. He glances at Allison, signaling for her to begin, and moves to plug his laptop in, connecting it to the projector.

"So, as of yesterday, there has been five individual killings connected to our killer." She hands Hale four folders holding the copies of the case, and the fed rations them to the rest of his team. "The first murder was committed fourteen months and a eleven days from today, June last year, and from there on the second murder about five months later, then four months later, then two, two and now just one."

"First victim: Daniel Kelly, twenty-eight years old, worked as a part-time bartender," Stiles takes over, displaying the victim's profile at the front of the room.

"Multiple stab wounds to the abdomen, died of profuse blood loss. He was found in the parking lot behind the bar he worked at by his employer." He shows pictures of the body, taken at the scene as well as at the morgue, and of the discarded murder weapon, as Allison starts speaking again,

"This was the killer's first victim, so initially it was believed to be a regular 187, or maybe a robbery gone wrong. It differs a little from the rest of the vics. The killer's work is a little shabbier than in the murders following Kelly's, which is to be expected if this is indeed his first offence. Also, the customary photo he leaves at the murder scene was missing, which implies that the killer hadn't yet decided on making the killings habitual. However, the matching stabbing wounds and the victim profile indicate that the culprit--"

"Wait a moment," Special Agent Lahey interrupts. "A photo? The files we went through before didn't mention anything about the killer leaving a photograph behind at the scenes."

"That small tidbit of information was purposely left out of the reports," Stiles says, voice carefully devoid of emotion. "But we'll get more into it in a moment. The next murder scene already had one, as has every scene since."

He glances at Allison and changes slides, a new face displayed on the wall next to him. "So, our next vic: Louis Fletcher, twenty-six, a librarian. Found near the edges of Beacon Hills Preserve, in a small park. Multiple stabbing wounds and a profile fitting the killers MO, and a picture stabbed into the trunk of a tree with the murder weapon."

Agent Reyes tilts her head when Stiles shows them a picture of the photo stabbed into the tree. "That looks an awful lot like...."

Stiles nods. "Yeah, it's me."

Special Agent Hale's eyes suddenly snap to his face, clearly intrigued by the turn of events. He looks down at the papers spread on the table before him.

"I see there's a clear resemblance between the vics and yourself, detective."

Stiles swallows dryly before answering. "Sharp of you, Agent Hale."

"Interesting," Agent Boyd comments, and Stiles wants to bark out a laugh. He refrains, though.

"I'm sure it is," Allison says a little sharply, and that is enough to get everyone's attention to the presentation once more. "Forensics connected Fletcher's murder to Kelly's by the method of the murder, and we got assigned the case, since we had been the pair investigating Kelly's murder."

Stiles nods and changes slides to start describing the other victims; Dennis Coleman, 30, found dead in an alleyway; Elliot Myers, 23, found dead on the gravel under a bridge, and their latest vic; Sam Malone, 24, found dead in that alley from yesterday.

Stiles suppresses a shiver as he shows the picture of himself left at the newest murder scene. "This was taken last week when I was running errands with my friend." When he had been _unarmed_ , and with Scott of all damn people. His friend was too much of a puppy to hurt a fly, and even with a self-defense course under his belt, Scott was still all marshmallow-y softness and goodness on the inside. Sure, he would defend himself and Stiles if needed, but he didn't deserve something like that. Not a softie like Scotty.

"To me, it seems like your guy is getting impatient," Hale says as he eyes the picture displayed at the front. "The intervals between the killings have increasingly grown shorter during the fourteen months since the first murder."

"We know that--" Stiles starts to stay, but shuts up when Hale's piercing gaze nails him in place.

"He's not getting the same rush from killing anymore. And that means that he'll be soon coming for the real thing."

The agent says it with such certainty that Stiles feels cold sweat breaking on parts of his body. He licks his suddenly dry lips and breaks the staring contest with Hale to look down at his hands instead. "I know."

"Do you have a list of suspects?" Boyd breaks the silence by asking.

"Dead-ends, is what we have," Allison says. "This guy is good, and he's been toying with us for months. He's elusive and unpredictable, and impeccable when it comes to leaving no evidence behind. No one has seen him, no one has any tips, and his every victim has ended up at the morgue."

"Sounds like a damn ghost," Lahey comments with a frown, and Stiles shrugs at him.

"Might as well be, since we have nothing. Nada," he says bitterly and taps his fingers anxiously against the table before him. He notices Hale eyeing the movement, so he stops.

"We have gone through every guy that Stiles is responsible for putting behind the bars and the people closest to them, and then some. We even checked some high school and academy rivalries, but there's nothing to connect these people to the murders."

Hale breathes out slowly, glancing at the papers scattered on the table by his elbow. "We'll do our best to catch this unsub behind these murders, detectives. If you'll excuse us, I need to confer with my team."

Stiles narrows his eyes. "Are we not privy to this joint investigation, Special Agent Hale?"

Hale spares him a glance for his troubles. "I'm not sure whether you should even be allowed to continue working on this case, given that you're clearly rather too much involved."

"Excuse me?" Stiles presses and takes a heated step forward, but Allison moves to stand in his path.

"With all due respect, _Sir,"_ Stiles is kind of jealous for the sarcasm Allison is able to infuse into her 'sir', since sarcasm is supposed to be his speciality, "but I believe that letting Detective Stilinski go regarding this case would prove quite detrimental to solving it. He's by far the most invested person in this case, be it in good or bad, and he has quite the detective skills too, if you ask me."

Stiles suppresses a smile as he listens to his partner, and then scowls when Hale eyes Allison sharply and self-assuredly, preparing to reply her.

Finally, the fed sighs long-sufferingly, as if he's far too used to listening to nagging subordinates, but doesn't look too affected by Allison's statement. "Don't worry, detective. Stilinski will be staying on the case. I'm sure he is quite competent, as surely as are you. Also, I wouldn't want his father on my back if I kicked him off the investigation."

Stiles clenches his jaw. Who does this jerk think he is, talking about his dad like that? Chief Stilinski would never favor people, be it his son or not. "Are you implying something, agent?"

Hale turns his sharp gaze in his direction. "I assure you, I'm not."

Stiles scoffs, not buying the reassurance. "Let's just get on with this. You can start _conferring_ , or what ever. My partner and I will be listening in."

Hale does something that looks like an aborted eye roll, but motions for the two detectives to take a seat like the rest of them. They do, and so they begin brainstorming the case.

**Notes for the Chapter:**

> Yeah, Derek seems a little like an asshole in this one, but he'll come around soon, pinky promise. Updates next week :)
> 
> Thanks for reading! How did you like the first chapter?
> 
>  
> 
> [My tumblr.](https://cannibalpasta.tumblr.com/) Mostly Marvel stuff at the moment, but maybe that'll change once I get on with updating this fic more.


	2. Doppelgänger

In the end, Stiles has to admit that maybe Allison had been on the right track, at least somewhat. A fresh set of eyes had been helpful, and they had spent the whole morning and a good chunk of afternoon going through the files, victim profiles and the evidence Stiles and Allison had prior requested to be delivered to the conference room. Boyd and Hale had upgraded the killer's profile, and based on that they had even compiled a small list of most likely suspects. Suspects most of which had already been interviewed regarding the case, let it be said, but a list nevertheless.

Stiles pops his joints in an attempt to loosen stiff muscles caused by sitting all day thus far. It's now around 3 PM, and he's getting more coffee from the break room. Apart from the first cup of the day, caffeine really doesn't have the traditional effect on him it has on other people, since it interferes with his ADHD medication, but he still gets a kick out of drinking it, and the act itself seems to ground him at times.

He hisses at his burnt tongue after the first sip, and risks adding another packet of sugar and stirring the hot beverage furiously in hopes of cooling it.

"Still got coffee in there?" a male voice asks behind his back, and Stiles peeks over his shoulder to take in the bushy eyebrows and the chiseled jaw of Agent Hale.

"Knock yourself out," he says and moves out of the way, so that the half-full coffee pot is in Hale's line of vision. "It's shit but it'll do the trick."

"Just like back in San Francisco, then," the other man replies easily, and Stiles almost chokes since _was that just now an attempt at humor?_ He didn't think Muscles McStoneface was capable.

"San Francisco, huh? I took you as more of a Los Angeles guy. Maybe even New York."

"I'm actually from around here, believe it or not. Although, I did live in New York for some time, so I guess it's rubbed off on me."

What is this? Why is Mr Perfect sharing personal information with Stiles? "Oh, really? That's nice, I guess." He eyes Hale as the agent takes a sip of his coffee, which he seems to prefer black and without any sugar, the bastard. He's borrowing another detective's mug from the office, but Stiles has never really cared much about propriety, so he doesn't comment on it.

"Sure," Hale replies and leans against the counter. Stiles gulps down some more coffee, grabs another packet of sugar, and flees the break room just as Lahey enters. He has some paperwork regarding other cases to be done, as it is.

 

* * *

 

The next day, they assemble a large display board in the office, using markers and magnets to visualize connections between cases, suspects and everything involved. Stiles' own, smaller and much messier board for the case gets cannibalized for the sake of the bigger board, but he's too busy wracking his brain with the rest of them to even bat an eye.

They visit the morgue and forensics with Lahey, and even get Danny, their tech guy, to get them the security footage from the scenes it's available from. It's not much of use, since Danny doesn't come up with anything new. It's the same grainy picture Stiles has seen at least a million times, displaying a man of average height and average build, perhaps a little on the bigger side, with a hood over his head and gloves covering his hands.

Stiles surveys the board from his desk, hands busy with his stress ball. It's a replica of an ECD Mint lacrosse ball, one of which Scott had gotten him as a joke. He has the real thing in his desk drawer too, but at the moment the squishy one feels more comfortable in his hand.

It's the day after that when the interrogations start. Agent Reyes is mostly in charge, although Boyd steps in to help occasionally when Reyes decides that having him in the room with her will do them good. Hale of course is supervising the whole ordeal. Stiles joins him in the observation room to watch the interviews, and they listen in silently side by side.

The first day of the interviews goes rather quickly, and Stiles decides to fall back when Allison and the team leave for their home and their motel rooms, respectively. He's standing before his desk, trifling through case files and adding finishing touches to the display board when a familiar pair of detectives walks into the otherwise empty office.

"Burning the midnight oil again, Stilinski?" Detective Greg Carter asks him. His parter, Detective James Brett, discards his weapon, slipping it securely inside the drawer of his desk.

"Afraid so. But I see I'm not the only one."

Brett chuckles softly. "Just wrapped up a triple homicide. Although, the paperwork is going to be a bitch."

"Don't remind me," Carter groans and shoots an agonized look in Brett's direction. "We were about to go and celebrate with a couple of cold ones, actually. Care to join?"

Stiles considers the offer for a moment. He's not exactly buddy-buddy with the two detectives, but they have gone out drinking before, so asking him to join them is nothing out of the ordinary. "Nah, you guys go ahead. I have some stuff on my mind, as it goes."

Carter's eyes flit over the board before Stiles, and understanding floods his expression. The detective knows about Stiles and Allison's ongoing case. "Yeah, sure. See you around, Stilinski."

"Yeah."

It's not even five minutes after the two detectives have left when another person enters the office floor, but this one is silent. Stiles doesn't hear him approaching until he speaks softly behind his back,

"You're still here?"

Stiles jumps and twists around, hand automatically levitating to his flank where his holster usually is. Now, it's discarded on his desk, so his fingers grasp at nothing but air. Luckily, there's no need for anything else.

"Hale!" he lets out in one large breath, leaning down towards his knees a little in order to calm his racing heart. "Damn it! Get a bell, would you?"

"Sorry," Hale says, but his expression says smug instead of sorry. _Damn bastard_. "What are you still doing here?"

Stiles glances at the board over his shoulder, and shrugs at the special agent. "Working, duh."

"You should get some rest."

"Doesn't that apply to you, too?"

Hale levels him with a stern look, but Stiles remains unfazed. "I get my fair share of shuteye, I assure you."

Stiles turns a little so that Agent Hale won't catch him rolling his eyes. "Yeah, yeah." Hale spares him another glance before turning and walking towards the break room. The light is switched off, since it's off-hours, so he clicks it on before entering.

"Coffee?" he asks, twisting slightly towards Stiles.

Stiles purses his lips, but follows after the other man. "Sure."

The pot is empty, so they have to stand around for an awkward moment while the coffee brews, but after that Hale is quick to pour them a couple of mugs.

"Thanks," Stiles says as Hale hands him his mug back, taking an appreciative inhalation through his nose as he brings the drink close to his face. Hale watches him for a moment before nodding.

"Of course."

"So, a busy couple of days, huh?" Stiles inquires conversationally.

"Same as usual, I'm afraid. Being the senior agent, I really don't have that much of a free time."

Stiles huffs. "I see." Then he cocks an eyebrow in thought. "How old are you anyway? You don't look that much of a senior compared to your colleagues."

"I'm thirty-three. You, then?"

"Twenty-seven." When Hale raises one questioning, bushy eyebrow, Stiles shrugs and elaborates, "Detective Argent and I are the youngest detectives in the department. But we are not to be underestimated, just so you know! Especially Ally. She'll bite your head off if she so much as feels like it." He goes as far as pointing an accusatory finger in the other man's direction.

The agent surprises him by huffing out a soft laugh. "I'll keep your warning in mind, detective."

Stiles hums and takes a scalding sip from his coffee. He feels way too smug about the fact that he managed to shake a positive reaction out of the marble station that is Special Agent Hale.

The fourth day of the FBI agents' stay, the interrogations are officially finished, and Reyes and Allison take good care of compiling all the new information gathered from the interviews and slathering it on their board. Stiles doesn't find it particularly helpful, since to him it strays from the main investigation, but who knows. Maybe his gut is wrong and the killer is indeed one of the people Reyes has gone through the trouble of interrogating during the last couple days.

As it is, Boyd has been working on his own little investigation, conducting it in tandem with Reyes, asking questions from the victims' families and friends and trying to find out if the vics had been making any new acquaintances before their deaths. For all expect the two newest murders, memories have begun to grow fuzzy, and even though the idea is good, it isn't exactly fresh. It's precisely what Stiles and Allison had done previously.

All Agent Boyd finds out is that the third vic, Coleman, had suspected that someone was following him, and nothing else. Until he gets around interviewing the newest victim's family, that is.

The best new knowledge, hands down, is gathered from the said freshest victim's, Sam Malone's, younger sister, Sarah, since she tells them that he'd recently met someone at a local bar, although he hadn't mentioned any names or details about the guy's appearance. Just that the person was male. The lead is feeble at best, but it's better than nothing, so they decide it's worth taking a look.

The investigation is supposed to be somewhat covert, so they elect that only two should go visit the bar, and that they should go in their civvies. Stiles is adamant on going, and during the few days spent in close quarters with each other, even Hale seems to have subdued somewhat to Stiles' willful nature, so they let him have his way. Hale himself is the other one to go, since everyone in his team is busy, and given that it's a joint operation the pair should probably includes a member from both parties involved.

So, the two of them agree that Hale will come pick Stiles up from his apartment at 7 PM, and from there they'll head down to the bar Sarah Malone had told them to go to.

It's 6:58 PM when Hale's car, a _fucking Camaro_ of all cars, stops before the apartment building Stiles lives in, and Stiles quickly climbs into the passenger seat. While the detective is clad in chinos and a comfortable flannel over his t-shirt, Agent Hale is rocking a pair of tight jeans, a v-neck and a leather jacket, since of course Hale's the leather jacket type of a guy.

"All ready?" Hale asks him, although he's already speeding off.

"Yeah, sure."

They arrive at the bar maybe fifteen minutes later, the name _Ronnie's_ displayed with bright blue and red neon lights, and they step right in through the well-aged wooden door. Stiles takes in the inside of the bar quickly, before walking up to the bar itself.

"Hey," he brightly greets the graying bartender, and even adds a goofy smile he often wore as a teenager to sweeten the deal. "You must be Ronnie then?"

The gruff man, maybe in his mid-fifties, cocks an eyebrow at him. "That's me, alright. Now, what can I get for the two of ya?"

"Black Label. Neat."

"I'll have the same," Hale says as he slides down to sit on the barstool next to Stiles.

"See anyone eyeing me obsessively?" Stiles asks as Ronnie turns away, only half-joking.

"Surprisingly enough, no, I don't," Hale replies dryly and grabs them a pair of coasters despite the bar being what it is, the neat freak.

Ronnie returns with two tumblers of whiskey and places the glasses before them. "So, what are you kiddos doing in this part of the city then? It's not often I see new faces down here."

"Actually, we're looking for someone. Do you think you could give us a hand?" Hale asks the man, fingers skimming the ridge of his tumbler.

"That depends, kid. Shoot away."

"It's about one of your regulars," Stiles says. "Does the name Sam Malone ring any bells?"

"Ah, yeah that kid. Sure it does, he comes in every week. Always smiling, that boy."

The exasperated yet affectionate tone makes something twist in Stiles' stomach. "Lately he's been having company. You know anything about them?"

Ronnie looks up as if in thought. "I remember this one fellow, yep. Didn't catch a name though, if that's what the two of ya are after."

"What did he look like?" Hale presses.

The bartender shrugs. "Brownish hair, white skin. Looked the same as half of my other patrons, to be honest with ya." He barks out a laugh. "Younger, though. Maybe the same age as Malone. Maybe a little older."

A customer walks up to the bar and Ronnie walks over to serve him, and Stiles takes the moment to turn towards Hale.

"Could be our guy."

"Could be, or could not," Hale says, and takes a sip of whiskey. "Still not enough certainty." Ronnie walks back up to them.

"So, what's with all the questions? You two work with the police?" he asks, as if it just occurred to him. The pull out their badges and show them, and Stiles braces himself.

"Malone is dead," he tells Ronnie, and feels bad since the man looks a little pale at the admission.

"Lord almighty...." he murmurs softly as he frowns at the two of them. "That's a damn shame."

"It is," Hale agrees, and Stiles nods, because it truly is. They leave shortly after that, leaving a hefty tip and giving their numbers to Ronnie, in case the man seen with Malone returns, as they part, and Stiles feels somewhat better once the slightly damp evening air hits his face.

"We need to catch this guy," he says, deeply in thought as they walk to Hale's Camaro.

"I'm aware," Hale replies in his customary grumpy fashion, and buckles up while Stiles is still scrambling to get inside the vehicle. They drive in silence until Stiles' stomach decides to proudly broadcast its emptiness to everyone audible.

Hale smirks a little, but his eyes don't stray from the road ahead. "Hungry?"

Stiles feels a mortified blush creeping up his cheeks. "I haven't actually had the time to eat proper today, so yeah."

"Wanna stop by somewhere to catch a bite?" Stiles feels his eyes widen slightly at the offer, since _is Hale catering to his needs?_ What happened to the growly bear of a man he met just a handful of days ago?

"Sure," he ends up saying, and Hale drives to a nearby burger joint that's still open. There, Stiles orders a burger and fries, while Hale gets sandwiches and fries.

"You can't get sandwiches in a burger joint, Hale!" Stiles protests, but Hale just smirks at him from across the booth.

"But I just did," he replies smoothly, to which Stiles just answers by rolling his eyes. All in all, the evening turns out to be surprisingly pleasant, and Stiles really can't complain about the excellent view across the table either.

When the fed finally drops Stiles off at his place, it's well past 10 PM, but it's still earlier than what Stiles is used to getting home at.

"Good night, Stilinski," Hale tells him as he gets out of the car.

"Night, Hale," Stiles replies, and can't quite wipe off the stupid grin from his face as he walks up towards his building.

 

* * *

 

It's a few days after that, precisely one week and one day after the death of Sam Malone when the serial killer strikes again.

It's barely three in the morning, and Stiles is suffering from a serious case of bedhead as he arrives at the murder scene. Allison, Hale and Lahey are already there, and they are looking decidedly grim, even for a crime scene.

"What's up?" Stiles asks, but stops dead in his tracks as he sees the vic. Sure enough, he has stabbing wounds to his abdomen, but they look more hurried, more desperate than what's usual for their killer. But what catches Stiles off-guard, is how young the man looks. He doesn't look like he's even twenty, perhaps not even nineteen. But while he seems to be shorter than Stiles, and even though his eyes seemed to have been either green or blue instead of the warm brown of Stiles' own eyes, he can see the clear resemblance between the young man's face and his.

It's actually quite terrifying, how similar this young boy looks to him, and Stiles can't get a word out of his mouth before he turns his eyes away. He feels sick.

"Yeah, that's, uhm." It's probably not very convincing, but it's the best he's got at the moment, and he cards a slightly shaky hand through his hair in an attempt to calm himself. God, where does the killer find these men? And more importantly, when are they going to put an end to it?

"Stiles," Allison starts, but Stiles doesn't let her finish.

"I'm fine, Ally. Let's just get to work." He pulls out a pair of rubber gloves from his pocket and tries to subtly avoid looking at the dead body laying on the floor. The crime scene is a dusty, unused business space, but the large window has been cleared of all blockage and busted, so that the body was found quickly by a passerby. Stiles suspects that it was done intentionally by the killer.

A hand squeezes his upper arm, and Stiles turns to look back. Hale, of all people, is holding his arm in a consoling manner. He has the time to despair over the words the agent is no doubt going to say: 'Are you alright?', 'It wasn't your fault' or 'You're too invested' are his top picks, but the man surprises him yet again,

"We'll catch him," Hale says solemnly, and Stiles feels immensely grateful for that, be it true or not. He nods anyway, opting to not trust his words, and Hale's hand leaves his arm.

Once back at the office, Reyes and Boyd take a good look at the fresh crime scene photos, since they completely missed out the field work, only god knows doing what.

"Okay, I'll give it to you. The guy's completely obsessed with you, Stilinski," Reyes says as she trifles through the pictures, eyes lingering longest on the photos of the boy's face, as well as of the picture of Stiles left behind at the scene.

"Thanks," Stiles replies, voice dripping with dry sarcasm.

"When was that photo of you taken?" Boyd asks.

"After I dropped him off at his apartment building last Thursday," Hale answers, voice angry like he's vexed about the fact that the culprit keeps hiding quite literally in plain sight, and still managing to slip past unnoticed. Stiles can't really say he blames him.

"So, the unsub knows where Stilinski lives. Nice," Reyes comments.

Lahey hums. "It would've been a wonder if he didn't, given that this obsession has most likely been raging on for the better part of two years."

"The situation is getting out of control," Hale cuts in. "This murder was sloppy and poorly planned. It might work in our favor if it means that the unsub left behind evidence in his frenzy, but it might also mean that we are running out of time. He will kill again soon, and I'm not sure whether anything short from Stilinski will cut it this time." He looks at Stiles with steel in his eyes, and Stiles feels a little dizzy. From what, he's not sure.

"I'll go pressure Scott and Deaton down at the morgue. Lahey, wanna tag along?" Allison offers and Stiles watches as the two of them walk to the elevators. He sighs and decides to get coffee from the break room, since he still hasn't gotten his first cup of the day.

A moment later, Hale walks through the door also, going straight for the coffee machine like Stiles just a minute earlier. He sits down next to Stiles by one of the round tables in the room, taking a sip from his mug.

"I'm beginning to suspect that the shit they serve here as coffee is actually better than the shit in San Francisco."

Stiles snorts. "I doubt that, Agent Hale."

"Derek," Hale seems to blurt out. Stiles shoots the senior agent a confused look. "My name is Derek."

"Oh. Well, I'm--"

"Stiles, yeah, I know that," Hale cuts him off, and Stiles isn't even mad because Hale calling him by his name sounds illegally delicious. "What kind of a name is that anyway?"

Stiles scoffs. "I'll have you know, that it is a perfectly reasonable name to be called when your given name is such a horrible tongue twister as mine's."

"So, it's a nickname then?"

"Well, I guess by definition. But no one calls me by my given name, not even my dad." His dad, the sadist, giving a kid name that hard to pronounce. Geez.

"Does that mean I can call you that?"

Stiles pauses mid-intake of a breath, and zeroes in on Hale. He looks serious, and Stiles really doesn't understand what's going on.

"Yeah, sure, why not. And Derek, then?"

Hale --no, Derek-- flashes him a small smile, _a smile,_ a small one, yeah, but still _a freaking smile_. Not a smirk or a huff, but an actual smile. Stiles's worldview is once again reset.

"Are you sure you aren't being impersonated by some doppelgänger?" With that the spell is broken, as Derek rolls his eyes at him and gets up, coffee mug in hand.

"I'm sure, Stiles."

"That's exactly what an evil doppelgänger would say, though!" Stiles calls after him.

"Drop it, Stilinski!"

Stiles giggles to himself, and doesn't even notice how much his spirits have improved because of the short exchange between himself and the FBI agent.  


* * *

 

"Stephen Ray, nineteen years old, a student at Beacon Hills City College. Cause of death: multiple stabbing wounds to the abdomen and the following blood loss." Allison hands him the report she'd been reading out loud when he reaches for it with his hand. _Nineteen,_ he thinks sadly. It sounds too young, even if it's only four years junior to Myers, their former youngest victim.

"Boyd, Erica, get in contact with his parents," Derek tells his two team members.

"Okay, boss."

"Roger."

"The rest of you, let's get profiling our unsub again." Stiles doesn't argue with the direct command, which is apparently enough to earn him a somewhat concerned glance from Derek. "Isaac, recap."

"Male between the ages of twenty to forty, perhaps Caucasian with brownish hair. Medium height and weight, but strong enough to physically restrain his victims before the act of killing itself. Perhaps knowledgeable with knives, especially hunting knives. Knows Stilinski by some connection. Intelligent, obsessive, unstable...."

Allison walks in front of the list of suspects, pinned to the display board with a magnet. "That doesn't fit one soul on our suspect list."

Stiles blinks and rubs his chin in thought. "Lahey mentioned him being unstable. Could it be that he isn't connected to any of the cases that I've solved, but is someone I've helped instead?"

Derek spares him a quick look, before walking up to the suspect list too. "That's a possibility. But that could mean we have no clues, whatsoever. Can you think of any specific people, Stiles?"

Allison and Lahey look a little baffled to hear Derek calling Stiles by his name, and so would Stiles, since the whole concept has yet to really sink in, but he's too busy raking his brain.

"Well, I'm a cop so I have met quite a lot of people. Not sure anyone unstable enough to turn murderous, though."

"Anyone, Stiles." Derek presses, suddenly standing way too close to Stiles. He doesn't step further from the agent, though.

"Uhm..."

"Matt Daehler," Allison pipes up. "He was involved in this one case as a witness. One strange guy, I have to say. Kept eyeing Stiles like a piece of meat, but something like this is definitely not up his alley."

"We should still look into it," Derek says and nods at Lahey, who moves to grab his laptop. "Anyone else?"

"Remember that Donovan guy, Ally?" Stiles asks. "He seemed pretty weird."

"Donati?" Allison confirms. "His father was killed, right? Yeah, he seemed unstable, alright."

"We'll have a look at him, too," Derek says and looks at Lahey again. He meets Stiles' and Allison's gazes. "Good work." The two detectives nod, even though Stiles doesn't really feel like he's doing a good work at all. It's because of him that six people are already dead, as it is.

"Stiles," Derek voice cuts through the sudden haze he finds himself in. A warm, gun-calloused hand grips the back of his neck firmly. "Stop beating yourself up. That's an order."

Stiles manages a snort. "You're not the boss of me, agent."

Derek smiles crookedly at him, and Stiles feels his breath catching in his throat. "Get to work, Stilinski." It forces a shaky smile out of Stiles.

**Notes for the Chapter:**

> Thanks for reading. Leave a comment! :)
> 
> I'm not sure when I'll be able to update next, but I'll try not to take too long. Please, be patient with me.


	3. Gut Feeling

**Notes for the Chapter:**

> Hi!! Sorry this chapter took a while, I've been quite busy with irl stuff (as usual) .... hope this chapter makes up for it *wink wink*
> 
> smut warning

It's that evening when Derek calls him on his cell, which is...new, to say the least.

"Derek? What is it?" he asks, the hand not holding his phone tightening around the cool glass of his beer pint. He's out with Allison and Scott, gossiping as usual (although Scott refuses to call it gossiping, but Stiles knows better). He's still in his work clothes since they got there straight from work, but his suit jacket is discarded on the seat next to him, and his sleeves are rolled up near to his elbows.

_"Where are you? I couldn't find you at the station."_

"Oh, yeah, we just left, uh, maybe half an hour ago or something. I'm with Allison and Scott." He frowns a little, swiping his index finger over some condensation on the surface of his pint. "Did you need me for something? Did something happen?"

_"No, nothing like that. I just don't want you out there without backup, with the situation being as it is."_

Stiles sighs. People constantly fussing about him is really starting to get to him. "Thanks, Derek, but I'm fine. I can take care of myself."

_"I know that you can, but--"_

"Have a nice evening, Derek," Stiles interrupts him, and hangs up before the agent can say anything else. He takes a sip of beer, frowning moodily.

"So, Agent Hale, huh?" Scott asks innocently from across the table. He's holding Allison by her waist, and they look the very image of madly in love and happily married.

Stiles huffs out a humorless laugh. "There's no such thing as  _so-Agent-Hale-huh_ , okay, Scott?" he snipes, glaring at his best friend, and Allison laughs to his face.

"There's nothing shameful in admitting to a little crush, Stiles," she says mock sweetly, languidly sipping her apple cider.

"Trust me, there are no little crushes either, Argent," Stiles tells her firmly, but she just shrugs, and Stiles can feel heat blossoming beneath the skin of his cheeks. He hopes the McCall-Argents will just decipher it as the alcohol affecting him, but let's be real here. They probably won't.

The three order one more round, although alcohol-free this time since they are supposed to drive home, chatting and jumping topics, before Allison starts looking increasingly more tired, her exhaustion amplified by the alcohol in her system.

"I guess we should head back home, then," Scott says easily, smiling fondly at his drooping wife.

"I suppose," Stiles replies and watches Scott gently shaking Allison awake again. "You guys go ahead, I'll pick up our tab."

"You sure?" Allison asks, meeting Stiles' gaze as Scott helps her slip her coat on.

"Yeah, I'm sure. My car is parked just out front at the lot. Also, I believe it's my turn to pay anyway."

"Okay. Good night, Stiles."

"Good night, buddy."

"Good night, you lovebirds."

He pays for their drinks and leaves the waitress a nice tip before slipping out of the bar. It's almost midnight, so the air is comfortably cool against his warmed skin. Although the effect is ruined, since as soon as he steps outside, his gut twists with the feeling of trepidation. He turns slowly around, feigning nonchalance and checking his premises as his heart starts beating faster. It's quiet, too quiet to Stiles' liking, but there's no one suspicious around that he can see.

Many would argue that his worry is for nothing, since whose -- police or not -- gut really is right hundred percent of the time, but Stiles doesn't feel like taking his chances on this one. Especially with a serial killer on the loose. So, he pulls out his phone, sees Derek's name in his recents, and calls him. He frowns as he realizes just  _who_ he impulsively decided to call for help, but it's already too late since the beep against his ear cuts off abruptly.

 _"Stiles? Is everything alright?"_ Derek picks up just before the second ring.

"Yeah, I'm fine. It's just..." He wants to groan. This was stupid. "I've got this feeling," he finishes lamely. A couple of patrons are exiting the bar, so Stiles moves away from his spot in front of the door to let them through.

_"A feeling?"_

"I'm at the parking lot of _The Crown_. Got an ominous gut feeling and I thought I'd give you a call."

 _"Stay still and don't hang up. I'll be there in ten,"_ Derek replies curtly, and before Stiles can protest, he hears Derek setting his cell down, and presumably pulling on a coat or some shoes. He's not even sure whether Derek was still at the precinct when he called, furthermore was he even _up_.

After a moment Derek's voice returns. _"Alright, I'm getting to my car. You still there?"_

"Yeah, I'm here. Were you still at the office?"

_"Yes. Are you with McCall and Argent?"_

"No, they left like, not even fifteen minutes ago."

 _"Damn it. You should get back inside."_ Stiles hears a car door shutting from Derek's end of the line, and then the sound of the Camaro's engine firing up as Derek turns the keys in ignition.

"I'm gonna take a look, Derek," Stiles says, cementing his decision. He's already walking away from beneath the protective shelter of the overhang.

_"What? No. Stand back now, Stilinski!"_

"I'm sick of this game. Maybe we can catch him this way. You're not even ten minutes away, right? I won't drop dead that quickly. Plus, it's just a stupid gut feel, might be nothing."

_"Damn it, Stiles, you're being an idiot. Get inside the bar, now!"_

"Bye, Derek," Stiles says and hangs up the call. He draws in a breath and starts walking towards his car like he has no worry in the world. It's his work SUV instead of his personal car, his Jeep, and he had parked it on the other side of the lot as he and his friends had arrived.

A bead of sweat forms on his brow as the distance to his car grows shorter. He can feel his cell vibrating in his pocket, Derek no doubt calling after him.

"Stilinski!" he hears from behind his back, and he quickly turns around to face the man calling him, heart racing.

"Carter," he breathes out, eyes darting around the parking lot, but he sees no one else anywhere. Carter, his fellow detective, frowns at him as he closes the distance between them.

"Everything alright?" he asks, grasping Stiles' shoulder in one large hand.

"Y-yeah," Stiles replies, still a little dazed. "I just thought...." He looks carefully at Carter's perplexed face. "Never mind. What are you doing here?"

"I was going to meet with Brett at _the Crown_. You headed home, or will you join us for a drink or two?"

Stiles doesn't have the time to answer, since in that moment Derek's Camaro's tires screech as he brakes violently, and Stiles is sure that the agent must have violated every single traffic law and speed limit to get here this quick.

 _"Stiles!"_ he yells as he gets out of the vehicle, eyes zeroing in on Carter and the hand still on Stiles' shoulder. The look he sends the other detective's way screams bloody murder, and Carter must notice it too since the hand lifts off of his shoulder.

Stiles turns to look at the other man again. "Sorry, Carter, I'll have to take a rain check on that offer. Wouldn't want to upset the angry fed any further, right?"

Carter huffs out a laugh, but nods. "Right. See you around, Stilinski."

"See you." He watches as Carter starts walking towards the bar's front entrance, and completely misses the previously mentioned angry fed advancing him. Derek grabs him by his collar and slams him against the car nearest to Stiles, eliciting a groan from the shorter man. "Easy on the goods, man..."

"Shut up. You disobeyed a direct order--"

"You're not exactly my supervisor, Derek, believe it or not--"

"I said _shut up._ What if you had gotten yourself killed? What's the point in that?"

"Relax, it was just a dumb feeling. And see? I'm just fine!"

"You know those feelings aren't usually just for nothing, right? An experienced officer can often unconsciously pick up different indicators from their environment that form a general feeling of the scene. It's not to be taken too lightly, not even if you're not consciously noticing the signs of danger, as you're ought to know. Furthermore, I told you to wait for me--"

"Well, maybe I wanted to finally catch our guy, who knows! Now, enough with the lecture, let go of me!" He struggles and wiggles against Derek's hold, but the other man is relentless. In the end, Stiles just ends up more firmly plastered against Derek's chest.

"You were being a complete fool," Derek accuses, but now his tone sounds more resigned than anything. He even manages to look a little worried, beneath all the grumpiness. Or maybe it's just the dim lighting playing trick's on Stiles' mind, who knows.

He licks his lower lip in thought, and notices Derek eyeing the motion. He blinks. Breathes in. "Yeah, I know," he replies finally.

They stand like that for a moment, staring each other down, chests flush until Stiles finally notices the intimacy of their position. He clears his throat and wiggles a little uncomfortably.

And yeah, maybe that's the wrong thing to do, because as he wiggles his _fucking crotch_ brushes against Derek's.

"Stop," Derek bites out, voice sounding suspiciously rough as his free hand moves to grasp Stiles' arm.

Stiles narrows his eyes at Derek, his gaze searching. The agent's expression is meticulously unreadable, but when the man doesn't move to release him from his hold, Stiles decides to push his luck. "Stop what?" he asks and wiggles again, this time sending a small shiver of pleasure down his spine as he rubs against Derek. A mischievous glint is taking residence in his eyes as he keeps looking into Derek's hazel ones.

Derek growls, _fucking growls_ , and Stiles' knees go a little weak. But then, most fortunately, Derek is grabbing Stiles by the backs of his thighs and lifting him up, holding him firmly against the car. Stiles has about a millisecond to squeak at the sudden movement and prepare for what's coming, before Derek positions himself between Stiles's spread legs and _grinds_.

 _"Ah,_ " he groans, and Derek smirks deviously, letting out a small, breathy laugh. Stiles wipes it off by yanking him forward by his dark hair and sealing their mouths together. Derek moans into his mouth and presses Stiles even tighter against the side of the car. His hands move to cup Stiles' ass, and Stiles moans his appreciation, bucking his hips against Derek's.

Derek presses back and his tongue plunges into Stiles' mouth. The kiss is turning more and more heated and desperate by the minute, but neither of them do anything to change the fact. Stiles wraps his legs around Derek's waist and indulges the other man with another groan when Derek grinds down his hips again. Stiles thinks he might be running out of air when Derek grinds again, swallowing down the detective's moan.

Then the door to the bar clings open again, and Derek pulls his mouth away, hazel eyes locked with Stiles' brown ones. They pant for a moment there, hidden in the shadows of the parking lot as their breaths mingle between them.

"Maybe this isn't the best place for this," Stiles manages, and Derek huffs. He replies by ducking his head to lick a stripe up the side of Stiles' neck, finishing with a bite to his earlobe, and Stiles gives a whole-body shudder. "Uh, 'kay, so does that mean you disagree with me or...?"

"No, you're right," Derek answers and sets Stiles back down on his feet, much to Stiles' chagrin. "We'll finish this some other time."

Heat floods Stiles' veins at the words. "Promise?"

Derek bends a little to kiss him again, this time unhurriedly, although his arousal is quite evident thanks to the impressive tent at the front of his pants. Not that Stiles is faring much better, to be honest.

He tangles his hand with the agent's tie, holding him in place as they kiss, but lets the piece of garment slide from his grasp when Derek leans away again. "Promise. Now, get in your car. I'll make sure you get home safely."

Stiles sighs, but doesn't argue. He pats one of Derek's (impressive) pecs. "Sure thing, Special Agent Hale." His quip earns him a smack to his bum, and Stiles can't say he quite regrets it. 

 

* * *

 

The next morning the office is in a flurry of motion.

"What's going on?" he asks Allison, who's already at her desk, furiously scribbling away some report.

"We need a warrant."

Stiles feels his eyebrows rising towards his hairline. "For whom?"

"Daehler. Lahey and Danny stayed up all night investigating him, and they found some suspicious patterns in his behaviour."

"How so?" he asks levelly, although his heart is attempting to beat out of his chest.

"According to their research, he has completely isolated himself from the public during the course of a year, and he has recently purchased a vast variety of knives. Also, his father was a hunter, so that could mean he has some experience with different hunting knives."

Stiles swallows. Daehler could be their guy. Right now, he most likely _is_ their guy. But something about it feels wrong to him.

"What is it?" Allison asks. Stiles shakes his head.

"Nothing. I'll give Jackson a call, see if he can help us with the warrant." Allison grimaces in sympathy, but nods at him anyway.

Jackson Whittemore, having followed in his father's footsteps, worked as a lawyer in the DA's office, so the man had enough connections to different judges for Stiles' department's purposes. It was always a different matter though, whether Stiles would get him to cooperate.

_"Yeah, yeah, I'll talk to the damn judge if you'll just get out of my hair!"_

"Thank you, Jackson, you're the best!"

 _"You owe me one, Stilinski."_ And with that, he hangs up on Stiles. But the good thing is that they get the warrant the very same day.

Derek is the one to lead the raid, but the rest of them follow closely behind, along with Officer Yukimura and her colleague who stand by the curb near their vehicles. Stiles thinks that it's maybe a little excessive, but you can never be too careful with a possible serial killer, right?

"Daehler!" Derek barks at the closed front door, giving the wood of it a none too gentle knock. Matt Daehler lives in his parents' old home, both of whom have already passed away, but the yard looks like no one has stepped a foot in it for months. "Daehler, open the door!"

Stiles watches as Derek bangs his fist against the door, but no one answers. He locks his eyes with Stiles, and at Stiles' nod, kicks the door in. They are all wearing their bulletproof vests and everyone is armed, but they still move cautiously, pressing their backs against the closest wall once they get in through the front door. Stiles hears a crash and Boyd yelling, as the dark-skinned agent and Reyes come in through the back door.

"Clear!" Boyd's voice rings through the house. Derek lowers his gun, but doesn't slide the safety back on yet. They walk to where Boyd's voice was last heard from.

In the living room, there is the body of Matt Daehler, clearly not even past the twenty-four hour mark since his death. The body is slumped sideways on the couch, a large patch of yellow wallpaper painted red by spattered blood and brain matter behind him, and a chunk of tissue is missing from the back of his head. Stiles notices the bloody shotgun laying on the floor, as well as pictures scattered on the coffee table. Pictures of _him_ , but also pictures of the killer's victims. He sees a camera set above a cupboard by his right. Unused hunting knives by the wall.

It's all there. The evidence. But why does it feel so....wrong? Why does it feel too perfect? Too neat.

Allison is pressing a button by the side of the walkie-talkie attached to the kevlar covering her chest. "Detective Argent here, we have a possible 10-56. Requesting a CSI unit and forensics." She goes on to give dispatch the address, but Stiles is too confused to truly listen to her talking.

A warm hand touches the small of his back and guides him out of the living room and into next room over, which is the kitchen. He sits down when he's pushed towards one of the dining table chairs and focuses again when Derek crouches before him.

"You back?" he asks, eyes trained on Stiles' face as he cups his cheek. Stiles blinks at him owlishly.

"Something's wrong."

"What is?"

"I don't know. This thing is just....too neat."

"Stiles--"

"I helped this kid, Derek," he interrupts the other man, "He isn't a serial killer. And don't tell me that he isn't a kid, because he fucking is!"

"Stiles, he's twenty-five and on three different psych medications."

"You told me that that feeling, that it's rarely just nothings. Well, now I'm telling you Derek, that something feels wrong, okay?"

Derek sighs, but he seems to understand where Stiles is coming from. "Okay. But we still have to acknowledge the evidence, alright? We'll keep the case open for a while longer, but the higher-ups are going to want to wrap this up."

"Yeah, I know."

"Okay." Derek spares him another lingering caress and a look, before he returns to the living room to join the rest of his team. Stiles buries his face in his hands and indulges in a long sigh.

 

* * *

 

"I was right. There is something amiss here."

Derek swivels his chair around to look at him. "What do you mean?"

"The camera. It's too clean. Forensics only found a couple partial prints from Daehler. They could have been easily planted after his death. Otherwise, nothing."

"Maybe he just keeps his things tidy," Lahey shrugs.

"His phone wasn't particularly clean, though. Neither was his car, let me tell you," Allison interjects, scrunching up her nose at the memory.

"Also," Stiles continues, "all the evidence was centered in the living room. There were no photos anywhere else except the living room coffee table. Don't you guys find that a tiny bit odd?"

"You're saying the suicide was framed then?" Boyd asks.

Stiles fiddles with the papers in his hands. "Maybe."

"To me, it sounds like you're chasing your own tail, hon," Reyes quips, slurping her frappé obnoxiously. Stiles glares at her.

"Erica," Derek scolds, and Reyes subsides with an eye roll. Derek turns to face Stiles once more. "I'm afraid that's not evidence concrete enough, Stiles."

Stiles sighs. "Yeah, I know that." He drops the papers onto his desk and leans against it. "This whole Daehler thing just isn't sitting right with me."

Allison glances in his direction, then motions him over. When he bends towards her, she ruffles his hair.

"Stop worrying and help me finish this stack of papers." She pats the sizable pile by her elbow, and Stiles can't quite contain his groan. He helps anyway, because that's what partners do.

It's around 11 PM when Allison finally decides that she should retire for the day. Lahey, Boyd and Reyes have already left some time ago, and Allison, the devil, sends a devious wink in Stiles direction as she leaves him alone with Derek.

And, as it happens, on their trip to get coffee from the break room, Stiles ends up pressed against the wall, Derek's large hands roaming over his body as Stiles' own flounder to loosen the agent's tie. He groans when Derek's lips latch onto the sensitive skin of his neck, and shudders when he feels the scrape of teeth.

 _"Derek..._ " he moans when a pair of hands circle his body to grip his buttocks. He can feel Derek's thick erection pressing against his hip. "How is the station's break room better than a parking lot to you?"

"Is it not?" Derek replies breathily, panting hotly against the saliva-slick skin of Stiles' neck. "I would think it as an improvement."

"Uh-huh?" Stiles asks, already having forgotten what they were talking about. "Let me just...." he says as he disentangles himself from Derek. The other man looks confused for a moment, until Stiles falls down to his knees.

 _"Stiles..._." Derek groans, as if the sight of him on his knees is already too much for him. Stiles smirks up at him and starts undoing the agent's trousers. His breath catches in his throat when he sees Derek's member. It's nothing short from impressive.

"Woah," he lets out, half-involuntarily, and Derek chuckles.

"Still up for the challenge?" he asks, teasing, but Stiles notices that his voice is strained. Like he  _really_ hopes Stiles is up for it. And, yeah, it probably is pretty much obvious by now that  _hell yes Stiles is._

"Always, Agent Hale," he replies playfully and takes the head of Derek's cock in his mouth. Derek shudders and mumbles some curse that Stiles doesn't quite catch. He removes his mouth to trail his lips and tongue wetly over the underside.

"Stiles!" Derek groans, now sounding demanding and almost desperate, and Stiles takes pity on him. He fits his mouth over the head again, and takes in as much of Derek's length as he's able, using his hand to curl it snugly around the base that his mouth doesn't reach. He starts moving his hand and bobbing his head, and Derek hisses, hips stuttering as if he wants to fuck Stiles' face.

Stiles' dick, fully hard, twitches in his pants at the thought, and he reaches up with his free hand to grab Derek's hand, twisting it into the dark locks in the back of his head. Derek takes the hint, tangling his fingers with the strands and holding Stiles head in place as he slowly takes control with his hips.

At the first tentative thrust, Stiles moans around Derek's cock, and that seems to do the trick for Derek. He begins thrusting more surely, more forcefully, taking all that Stiles is willing to give.

"Stiles," Derek pants down at him after a moment, "I'm gonna...." He starts pulling his thrusts, so Stiles grabs his hips and pulls them closer to his face. He ends up almost choking himself, but as he swallows around the head of the cock in his mouth Derek's hips stutter, and he groans as he comes down Stiles' throat.

Stiles swallows as he waits for Derek to finish, and pulls back only when he has positively wrecked the other man. He looks up at the agent, panting with his mouth still obscenely open, and Derek meets his heated gaze. Then the hazel eyes fall down to the obvious bulge in his pants, and the agent smirks, pulling Stiles up.

"My turn," he says as he positions Stiles up against the wall, kneeling before him and pulling down his pants and briefs with incredible speed and agility. But then he's swallowing Stiles down whole, and Stiles really doesn't have the time or the mind to analyze the situation.

"D- _Derek_ ," he groans as Derek pulls him flush against himself with a hold he has on Stiles' ass. He uses the hold to coax Stiles' hips into a shared rhythm with his hands and face, and it's almost embarrassing how fast Derek gets him to the brink of coming. And when he does, Stiles bends from the waist towards Derek's back with the force of it. And when Derek still doesn't let up his sucking and fucking his face on Stiles' dick, Stiles almost sobs from the overstimulation, shaking and gasping where he's leaning over the other man. "Derek, _oh my god_ , please, I can't--"

Somewhere amongst there must be the magic word, since Derek finally detaches himself from Stiles, and lets him slide down the wall and into Derek's awaiting arms.

"That was...." Stiles pants after a moment.

"Yeah," Derek finishes, voice deliciously rough from giving Stiles head just a couple of minutes ago.

They sit there for a moment catching their breaths, before they at last have the energy to make themselves presentable. It's almost midnight, and Stiles decides that he's officially too lethargic to work.

"I'm gonna head home," he tells Derek once they are back in the office and he's packing up his papers.

"Okay. Text me when you get there."

Stiles rolls his eyes, but the action is mostly a fond one. "Yeah, yeah. I'll be fine." He leans into Derek's space for a kiss before walking away in the direction of the elevator.

"Good. See you tomorrow morning."

Stiles smiles at him over his shoulder. "See you."

He gets out of the building and walks up to his SUV. Only that once he touches the handle of the car door, he gets that same horrible feeling of trepidation. He turns to look around the mostly-empty-of-cars parking lot, but sees no one. He turns back, but just as he's about to slide into the driver's seat he's grabbed from behind.

He shouts and starts twisting in his attacker's hold, catching him with a painful kick into his shin. The man -- definitely a man because of his low voice and bulk -- grunts, but only tightens his hold on Stiles' abdomen. His other hand curls around Stiles' neck, the long fingers winding around the column of it like a vice.

The signs of struggle on the serial killer's victims flash before Stiles' mind's eye, and he doubles his efforts to free himself. He can't get to his gun, since his right arm is pinned beneath the arm circling his abdomen, but his left hand is able reach for his pocket where his cell is.

He knows that he won't be able to dial any numbers in this state, but he hopes the attacker will get spooked by the sight of the device and at the potential threat of getting caught red-handed. Surely enough, when he pulls the phone from his pocket, his attacker moves, releasing his neck in order to smack the device away from him, and Stiles seizes the opportunity to gasp in a lungful of air and smack the back of his head against the other man's nose.

The man groans and his hold around Stiles' abdomen loosens. The detective falls to his knees on the asphalt, still dizzy from lack of oxygen, but alert enough to pull out his gun from its holster. He twists around, but the movement makes him a little motion sick, and it gives his attacker a headstart.

He's gone before Stiles has even the time to catch a glimpse of his face.

He pulls himself against his SUV and with a shaking hand chooses Derek's number from his contacts. He's still gripping his gun tightly, trembling from adrenaline and shock, and wheezing from the strangulation when Derek answers.

_"Stiles? Is everything--"_

"I'm down at the parking lot. Get here now. Please."

**Notes for the Chapter:**

> What did you think? :)
> 
> not sure when I'll get the chance to update next, hopefully sooner than last time. Anyway, thanks for reading!


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